Stoker



F. H. BROWN Jan. 23, 1940.

STOKER Original Filed Dec. 21 1922 O O O O O O O O O O G O G I (3 O O OO O O O 0 O O O O Patented Jan. 23, 1940 I PATENT" OFFICE 1 STOKERFrancis H. Brown, Ridley Park, Pa.,, assignor to The RealEstate-LandTitle and Trust Company, Philadelphia, Pa., a corporation ofPennsylvania Original application December 21, 19,22, ,Serial No.608,228. Divided and this application Oc- .tob er 22, 1934 ,'Serial No.749,435

3.0lain1s. 7 (01. 110-35); 1 I I This invention relates broadly toconveying and distributing materiaL and more particularly pertains toimprovements in method of and apparatus for feedingsolid fuel, suchas'coal and 5 the like, to furnaces, such apparatus being com moniyknown'as stokers. A

While this invention is illustrated as embodied in an automatic stokingdevice for th'purpose of delivering and distributing fuel in a furnace,

- whereby toincrease the efiiciency and the utility ofthe'furnaca'it'wi-ll be readily understood that the inventionjis-notlimited to such an adaptation, but finds a wide field of utility forother purposes.

tages which characterize this invention-,arjef the provision of animproved apparatus for conveying and distributing material; theprovision of an improved apparatus for conveying and dis- 2o trimming fSuch a coal a e, like; t e pro: vision of an improved apparatus for v rg fuel, suchas coal, for use within a furnace; the provision of animproved apparatus for stakinga furnace; the provision ofan improvedappara iztus for delivering fuel to a furnace and "for distributing thefuel evenly in the furnace; the; provision of an improved {apparatus forintroduce looting the ash as formed in the fuel bed and dis:

iposing of the ash from a furnace; and the provision of andco-ordihatioh in a single furnace unit of improved apparatuscharacterized by the embodiment therein of co-ordinated mechanism" fordeliveringsolid fuel, suchas coal, tof the fur- 402112168, mechanism'for distributing the fuel thus delivered, and mechanism for collectingthe-ash as formed and disposingof the ash.

It is an important object of this invention to provide an improvedmechanism for sizing and "evenly and uniformly distributing thefueldelivered to a furnacaland to this end theinvention involves an improvedgrate bar structure; which is characterized by the provision of animproved formf revolving grate bars; the pro-5 50 jvision of groups ofrevoluble grate bar s for-dis-' tributing fuel through the furnace;' theprovision of a grate bar structure which operates to tie-- liver anddistribute fuel to a, desired point for consumption and during;consumption in a fur- 88 mace; and the provision; in a furnacegrate, of

Among the more important objects andadvan' aplurality of series ofparallel perforated revoluble grate bars adapted to rotate in the samedirection in each seriesan'd at. the samespeed relatively, for thepurpose of distributingand continuously advancing the fuel delivered tothe furnace, and for-the purpose of shaking out the resultant ash duringits formation.

A still further object of this invention which results in theattainmentof one of the principal advantages thereof, resides in the provision ofan improved grate structure for' removing the ash as formed anddisposing'of the ash from a I provide an ash disposal mechanism, which00- operates-with the improved grate bar structure referreditohereinbefore to withdraw the ash deposited therefrom, this improved ashdisposal mechanism involving structural features which will be pointedout more in detail later.

It will be understood that the fuel delivering mechanism and the ashcollecting and disposal mechanism may be employed in connection withgrate bar or furnace structure other than that illustrated and describedhere, but the fuel delivering, grate bar, and ash collecting anddisposal mechanism of this invention are particularly adapted forcoordination in a single furnace unit,

tural embodiment illustrated in the accompanying drawing, in which:

Figure 1 is a longitudinal sectional view furnace illustrating thisinvention. 1

Figure 2 is a detail fragmentarysection'view' of a grate bar. g

Figure 3 is a fragmentary sectional view taken on the line 3--3 ofFigure 1 inthe direction inf cheated by the arrows.

indicated by the arrows.

Referring more particularly to the -improved method of stoking a furnaceinvolve-d inthe pres ent invention, there is included the steps ofsizing and depositing continuously a required quan-- tity of fueL'suchas coaland therlike, in'a furnace; then the step ofcontinuouslyxagitating, conveying, and'thus distributing thefueluniformly throughout the furnace-fire box in order to attain alevelfire; and, simultaneously with such distribution and during'consumption'of the fuel, removing the ash from the entire area of thefire bed as such ash is formed, collecting, and disposing of theresultant ash, thus maintaining in operation a continuously clean, ashfree fire. In attaining the various steps outlined above, I provide astructural arrangement which comprises fuel sizing; and depositingmechanism, an improved grate structure, particularly characterized bythe provision of revoluble grate bars, arranged in multiple groups ofany desired lengths, and an improved ash collecting and disposalmechanism adapted to be operated, continuously if desired, with saidfuel feeding mechanism and grate. The ash disposal mechanism ischaracterized by the provision of means for separating differentqualities and sizes of ash during operation of the furnace, wheredesired.

This application is a division of my co-pending application S. N.608,228, now Patent No. 1,977,- 620, and the structure here described isparticularly adapted for the use of thehollow cylindrical grate barsdescribed therein and also more particularly described and claimed in myco-pending application S. N. 749,433. These grate bars as shown inFigure 2 herein are characterized by radial perforations I0 andintersecting abrading ridges II on the surface which are particularlyadaptable to the structure heretofore disclosed.

Referring now to the drawing, the furnace comprises a base portion [89in which an ash pit I90 is disposed. The fire box I9I is provided,having the usual arches, I9Ia and I92a, and above these arches the wateror firetubes I92 are arranged. Air enters the furnace at IBM throughconduit l9Ib to the space between the arches, and is thus preheated, therear of the arches being bricked up at l93a. The entrance I89a iscontrolled by a damper I92a, which latter may be manually orautomatically operated as required by the provision of a chain or cableI92b, trained over a sheave I92c. The superheated air thence passes fromthe space between the arches via ducts I93b tov the fuel at therespective entrances above the grates I95 and I96, thus entering thefire box I9I with the fuel. Air may also be admitted into the ash pitI99 below the grate structure through the openings I88, either in lieuof or as supplemental to the supply of preheated air as' may be desired.

Fuel inlets are provided on either side of the fire box I9I and comprisehoppers 293 and I94, said hoppers depositing fuel directly upon theouter end of the grate bar structures I95 and I96, these grate barstructures being constructed substantially in accordance with the gratebar structures fully described in my co-pending application S. N.608,228 now Patent No. 1,977,620, particularly as shown in Figures 1 and2 of that application.

The essential features of this grate bar structure is shown in Figures 3and 4, where each individual grate bar 5 is mounted upon a shaft 6 so asto rotate therewith. The shaft 6 is mounted in a bearing I mounted uponthe furnace wall. Also fixedly mounted on the shaft 6 is a gear 8 whichengages a worm 9 extending for the entire length of the grate structuresI95 and I96 and mounted in suitable bearings supported by the furnacewalls. Continuous rotation is imparted to the worm 9 by any suitablemeans such as a motor. The worm 9 is so cut that the grate bars in gratestructure I95 turn in a clockwise direction to propel the fuel in courseof consumption in the direction indicated by the arrow I, while thegrate bars in grate structure I96 turn in a counter clockwise directionto propel the fuel in course of consumption in the direction indicatedby the arrow J. The grate bars I98 and I99 are suitably geared to theadjacent bars of the structures I95 and I96 respectively to rotate inthe same respective directions. Also, the grate bar structure shown anddescribed in my copending application S. N. 749,434 may be readilyadapted to the installation shown in the application. Thus, the twograte structures progressively deliver fuel and the larger particles ofash to a central space I97 arranged between the adjacent ends of saidgrate bar structures. The ash passes between relatively large grate barsI98 and I99 and is deposited in a tapered hopper 200. The hopper 200 isarranged with its lower portion open and disposed above a longitudinallyextending screw conveyor 20I, arranged in a trough 202, and the ash pitI90 communicates, through openings 203203, with a jacket 204 surroundingthe trough 202, said jacket having a trough 205 at its bottom in which asecond screw conveyor 206 is arranged. A pair of doors or baffles 201are hingedly mounted on the lower ends of the wall of the hopper 200,and, as shown in the drawing, are intended'to deflect the finer ash,which is deposited in the hopper I 90. into the jacket 204, from whenceit is conveyed to a desired point by the screw conveyor 205. For thepurpose of delivering all of the ash to the screw conveyor 20I, a secondpair of bafiles 208 is provided and connected by the provision of links209 to the baffles 201, and when it is desired to deflect all of the ashinto the conveyor 2', the doors 201 are moved to the dotted linepositions, which closes the openings 203. This may tend to prevent thepassage of the larger particles of ash 'in the hopper 200, but as thedoors 20! do not entirely close the bottom of the hopper 200, but leavean opening at least as large as the space between the rollers I98 and I99, most of the large particles will be deposited in the conveyor 20LThus, it will be seen that the ash deposited from the grate structuremay be selected in accordance with its size for future use, and then beconveyed to the desired point. Thus the fine ash may be separated fromclinkers and cinders, or where the grate is used for coking fuel thefine ash is separated from the coke. This is rendered possible becauseof the nature of the revolving grate bars, as fully set forth in myco-pending application S. N. 749,433.

From the foregoing description and the accompanying drawing, it will beobserved that there is provided a fuel feeding device or stoker whichmay be readily adapted to various types of furnaces, and the provisionof the curvilinear grate bar surfaces increases the burning surface ofthe grate for a given area at least one-third over that ordinarilyattained, and at the same time, while revolving, does not vary thedistance between the bars, which would occur with fiat bars. Animportant feature of this invention resides in the function of the gratebars wherein they constantly remove ash as formed, so that not only isthe fuel properly sized and distributed to maintain a level fire andthus prevent holes, but the fire is always maintained free of ash. Thus,for all practical purposes, no clinkers can form.

It will be obvious to those skilled in the art that this stoking deviceis adaptable for use with various kinds of fuel, with any form or method'of draft, natural or mechanically produced and conveniently andeffectively responsive to any form of regulation, thereby affording ahighly efficient and dependable means for carrying out combustionoperation, whether for the purpose of producing power, or for use inconnection with 5 metallurgical, by-product processes and commercial andindustrial gas manufacturing.

Variations of the draft and other functions performed may be employed inoperation in conjunction with the device and may be accomplishedmanually or automatically in response to variations in one or morefactors incident to or resultant from the operation of the stoker and,the conditions of combustion prevailing. The manner of controllingdraft as shown in the drawing is purely exemplary of one manner ofcarrying out the principle involved.

It will be readily understood that the grate structure hereinbeforedescribed may be modified within the spirit of this invention for ap-'plication tovarious installations. It will also be understood thatwhile the fuel feeding mechanisms, grate bar structures, and ashdisposal mechanism are here illustrated as applied to a stationaryfurnace installation, they may be readily applied, by slightmodifications, to locomotive and marine boilers, metallurgical and otherfurnaces.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is:

1. In a furnace structure, in combination, a grate structure comprisinga plurality of series of rotatable grate bars and means for rotatingsaid grate bars, said bars being adapted to re- 5 ceive fuel at the endportion of each series and to deliver the fuel during consumption to themedial portion of said grate structure, and to remove the fine ashduring consumption, and ash collecting and conveying means associatedwith said grate, adapted to maintain the fine ash removed by the gratestructure separate from the 5 fuel residue delivered to the medialportion of the grate structure. 1

2. In a furnace structure, in combination, a grate structure comprisinga plurality of series of rotatable grate bars arranged substantially 10in a single plane and means for continuously rotating the bars in eachseries in a common direetion but the bars in different series inopposing directions with their upper surfaces moving toward an outlet atthe medial portion of said 15 grate structure, means for placing fuel onsaid grate structure at the outer end of each series of grate bars, andmeans associated with said grate for separating the ashes according tosize.

3. In a furnace structure, in combination, a 20 fire box, means fordelivery of fuel Within said fire box at a plurality of fuel entrancesremote from each other, a grate structure of rotatable grate bars andmeans for continuously rotating said grate bars adapted to receive fuelat said 25 entrances and convey the fuel during consumption tosubstantially the medial portion of the fire box while separating thesmaller particles of ash from the fuel, means for receiving and removingthe larger particles of ash at the medial 30 portion of said fire box,and means for continuously collecting and removing said smallerparticles of ash separate from the larger particles of ash.

FRANCIS H. BROWN.

